Web audio API: scheduling sounds and exporting the mix

Question

I\'ve been checking Web Audio API documentation and the tutorials but haven\'t quiet figured out how to approach this problem.

Let\'s say I load few wav files via XM

Answer 1

Just did something a bit like this.

Essentially, you'll need to create an offline context:

var offline = new webkitOfflineAudioContext(numChannels, lengthInSamples, sampleRate)

You'll have to recreate all your BufferSources using this new context:

var newBufferSource = offline.createBufferSource();
newBufferSource.buffer = someAudioBuffer;
newBufferSource.connect(offline.destination);

Then schedule your playback:

newBufferSource.start(offline.currentTime + 10);

Then bind to the complete event for your offline rendering:

offline.onComplete = function( ev ){
  doSomething(ev.renderedBuffer);
}

Then start 'rendering':

offline.startRendering();

Once you have ev.renderedBuffer, you can do whatever you want with it. In my app, I have a WAV encoder that I ended up writing myself - but you could modify Recorder.js to do the same thing pretty easily.

Just a heads-up: webkitOfflineAudioContext is Chrome-only at the moment. Here's a link if you're interested: OfflineAudioContext